Circuit breaker



Dec. 23, 1969 Filed Sept. 14, 1967 D. E. lCLARKE CIRCUIT BREAKER 7Sheets-Sheet l v5/QM, wie

Inventor, az/d E'. Clarke,

Mam.-

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Dec. 23, 1969 E CLARKE 3,486,150

C IRCUIT BREAKER Inventor', Baz/d E. Clarke,

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D. E: CLARKE G IRCUIII BREAKER- w -v c i' @me Sheets-Sheet .'5

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In ven tor,

David E Clarke,

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Dec. 23, 1969 D, E, CLARKE l 3,486,150

CIRCUIT BREAKER Filed Sept. 14, 1967 7 Sheets-Sheet 4 @9.11. 1 Ff'gd- /252 `52\ I ||I [lll] 6 6 44 8 y." w @a j y W49 /4 4g t /4 "60ml 36 22 22Z @2 za@ 69 22 3 H2 2 4 236 72 /26 H2 fyi?.

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Dec. 23, 1969 D, E CLARKE 3,486,150

CIRCUI T BREAKER Filed Sept. 14, 1967 7 Sheets-Sheet 5 AL- /40 L ,40 /40U0 In vento; /40 30 David E'. CZde,

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Dec. 23, 1969 D. E. CLARKE 3,486,150

C IRCUIT BREAKER Filed Sept. 14, 1967 '7 Sheets-Sheet 6 Inventor, Daz/idE. C'Zarie, y QQWRMMM Atthy.

I De@ 23, 1969 D'. E CLARKE 3,486,150

C IRCUI T BREAKER Filed Sept. 14, 1967 '7 Sheets-Sheet 7 5J @M @we umUnited States Patent U.S. Cl. 337-43 4 Claims ABSTRACT OF THE DISCLOSUREA miniature, trip-free, ambient-compensated multipole circuit breakerhas a plurality of compartments in each of which a bell crank latch isnormally engaged with an ambient-compensated catch for holding tixed andmovable contacts engaged to close a circuit. The bell crank latches aremounted for individual rotation on a common shaft, and, in eachcompartment, current-responsive means are adapted to release the catchfrom the bell crank to open the respective compartment circuit inresponse to overload current in the circuit. A plurality of cam means isadapted to be rotated when a catch is released from a bell crank inresponse to overload current in any one of the compartment circuits.Pairs of the cam means are interconnected for common rotation so thatrotation of any cam means upon opening of any compartment circuitrotates other cam means to release catch engagement with the bell cranksin other compartments for opening the other compartment circuits. Asingle manual actuating member is connected to the shaft to permitsimultaneous manual opening of all of the compartment circuits.

tions, the multipole circuit breaker device should be manually operableas a switching device, should be easily calibrated for automaticoperation in response to selected overload current and should beambient-compensated. The device should also be trip-free so that, whenthe device has opened a plurality of circuits in response to an overloadcurrent in one of the circuits, none of the circuits can be reclosedwhile the currentresponsive means in said one circuit remainsconditioned by the overload current. It is also important that suchmultipole circuit breakers be of small size relative to theircurrent-carrying capacity.

In a manually and automatically operable, trip-free, ambient-compensatedsingle pole circuit breaker described in the present inventors copendingapplication for patent, Ser. No. 504,632 filed Oct. 24, 1965, now Patent3,361,882, the disclosure of which is incorporated herein by thisreference, novel structural features are "ice utilized to achieve adevice of wide capability in a construction of exceedingly small size.While this earlier single pole device has constituted a considerableadvance in the art of miniaturization of circuit breakers, three-phaseand other multipole circuit breakers of corresponding current capacityand operating characteristics previously known in the art have been ofsignicantly less compact construction and frequently have occupied avolume twenty times or more greater than the volume of the describedminiature single pole circuit breaker.

It is an object of this invention to provide a new and improvedsnap-acting multipole circuit breaker for the protection of electricalcircuit components against transients, sustained overload, and shortcircuits; to provide a circuit breaker of the class described which isfully trip-free; to provide a thermostatic multipole circuit breakerwhich is ambient compensated; to provide such a circuit breaker which iseasily calibrated and adjusted for automatic operation; to provide sucha multipole circuit breaker which operates in response to currentconditions in a single circuit without -being affected by currentconditions in related circuits; to provide such a circuit breaker whichautomatically opens all phases of a polyphase circuit in response totransient 0r sustained overload current in any phase circuit; to providesuch a multipole circuit breaker which indicates when the circuitbreaker has automatically tripped; to provide such a circuit breakerwhich can be used as a manually operated switch without deleteriouseects on its function of responding properly to overload currents; toprovide such a circuit breaker which is economical to manufacture and isreadily adapted to mass production; and especially to provide such amultipole circuit breaker which is of small size, light weight, andexceedingly compact construction.

Other objects and advantages of the novel and improved multipole circuitbreaker of this invention appear in the following detailed descriptionof a preferred embodiment of the invention, the detailed descriptionreferring to the drawings in which:

FIG. 1 is a vertical section View of the multiple circuit breaker ofthis invention along the vertical axis of the circuit breaker;

FIG. 2 is a section view along lines 2 2 of FIG. l;

FIG. 3 is a section view along lines 3 3 of FIG. 1;

FIG. 4 is a section view along lines 4 4 of FIG. l;

FIG. 5 is an enlarged partial view, partially sectioned, similar to FIG.l;

FIG. 6 is a section view along line 6 6 of FIG. l;

FIG. 7 is a perspective View 0f a cam member incorporated in the circuitbreaker of FIG. l;

FIG. 8 is a section view along line 8 8 of FIG. l;

FIG. 9 is a perspective view of an arc shield incorporated in thecircuit breaker of FIG. l;

FIG. 10 is a section view similar to FIG. 4 illustrating the position ofthe circuit breaker parts in manuallyopened circuit breaker position;

FIG. 11 is a section view similar to FIG. 4 illustrating the position ofparts of the circuit breaker immediately upon opening of the circuitbreaker contacts in response to overload current;

FIG. 12 is a partial section view along line 12 12 of FIG. 11;

FIG. 13 is a partial section View along line 13-13 of FIG. 11;

FIG. 14 is a front elevation view of a catch means incorporated in eachof three compartments of the circuit breaker of FIG. 1;

FIG. 15 is a section view along line 15-15 of FIG. 14;

FIG. 16 is a partial perspective view of the circuit breaker of FIG. lillustrating cooperation of cam means in the separate compartments ofthe circuit breaker for opening all circuit breaker circuits in responseto overload current in one of the breaker circuits;

FIG. 17 is a side elevation view of a fixed contact incorporated in thecircuit breaker of FIG. l;

FIG. 18 is a front elevation view of the contact shown in FIG. 17;

FIG. 19 is a plan view of a combined mounting an adjusting bracketincorporated in the circuit breaker of FIG. l;

FIG. 20 is a side elevation view of the bracket of FIG. 19;

FIG. 21 is a section view along line 21-21 of FIG. 19;

FIG. 22 is a side elevation view of an assembly of the bracket of FIG.19 with other components incorporated in the circuit breaker of FIG. l;

FIG. 23 is a front elevation view of the assembly shown in FIG. 22;

FIG. 24 is a partial section view along line 24-24 of FIG. 23;

FIG. '25 is a front elevation view of a spring incorporated in thedevice of FIG. 1;

FIG. 26 is a side elevation view of the spring shown in FIG.

FIG. 27 is a perspective view of a 'bell crank member incorporated linthe circuit breaker of FIG. l; and

FIG. 28 is a diagrammatic view illustrating assembling of the springshown in FIG. 26 with the bell crank member shown in FIG. 27.

Referring now to the drawings, and more particularly to FIGS. I and 3,one embodiment of this invention takes the form of a thermostaticthree-phase circuit breaker generally indicated by reference numeral 10and includes a base housing or casing which may be made of any suitablystrong, insulating and arc-resistant material such as ceramic material,molded phenolic resin, or the like. For ease of assembly of the circuitbreaker into a complete device, the casing is preferably made ofclam-shells 12, 14, 16 and 18 and two insulating spacers 20. In thisconstruction as shown in FIG. 1, six clam-shell units of the fourdifferent clamashell constructions are arranged in pairs separated bythe spacers 20 and are held together by studs 22 and nuts 24 to formthree, circuit-breaker compartments 26, 28 and 30. The clam-shell unitswhen secured together in pairs in the manner -described cooperate inconventional manner in forming slots for receiving the xedly mountedterminal structures 32 and 34 as described in the noted earlier filedapplication for patent. The terminals are preferably but not necessarilyof the screw type as illustrated. The spacers 20 are relatively longerthan the clam-shell units as shown for separating the terminalstructures 32 and 34 associated with the respective circuit breakercompartments.

Oppositely of the terminal structures 32 and 34, the clam-shell unitsform molded shoulders 36, these shoulders being received within matchinggrooves in plugs 4U and in the neck structure 44 for securely mountingthe plugs and neck structure on the casing. The neck struc-- ture 44comprises the mounting for a manual actuating means and a mechanicallatch hereinafter described. The neck structure is also externallythreaded as shown for use in mounting the circuit breaker 10 upon acontrol panel or the like as will be understood. In order to keep theneck from turning in the casing, the neck is provided with at portions46 as shown particularly in FIG. 2, these flat portions cooperating withmatching flat portions on the clameshell units to prevent rotation ofthe neck structure on the casing.

In accordance with this invention the neck 44 is provided With coaxialbores `48 and S0, and a manual actuating means 52 is movably mountedwithin the neck bores. As shown particularly in FIGS. 4 and 12, themanual actuating means 52 includes a push-button 0r head 54 and acylindrical metal sleeve 56, the push-button preferably being formed ofan electrically-insulating phenolic resin or the like and being attachedto the sleeve by means of a screw 58. In a preferred construction thehead of the screw 58 is set within a recess 60 in the push-button 54 anda cover 62 is press-fitted into the recess to prevent tampering with thescrew. The sleeve 56 is preferably provided with a longitudinal keyway64 and a key 66, formed by an upsetting operation on the neck 44, itsinto the keyway to permit axial sliding movement of the actuating means52 in the neck While preventing rotation of the actuating means in theneck as described in the noted earlier tiled application for patent. Thesleeve 56 is provided for a portion of its length with a bore 68, and alatch plunger 70, preferably made of hardened steel, is slidablyreceived in the sleeve bore 68. The middle portion of the latch plungeris fashioned as shown in the form of a pair of coaxial cones Whoseapices are joined. In addition, a connecting link 72, preferably formedof a molded, tough, insulat ing material such as phenolic resin or nylonor the like is attached to the latch plunger by any suitable means. Ahole 73 is provided through the end of the connecting link and asuitably dimensioned slot 74 is also provided in the connecting link sothat the connecting link forms a clevis or yoke. The sleeve 56 slidablein the neck 44 preferably has a smaller diameter portion at one endforming a shoulder 78 to bear against the compression spring 80, theopposite end of the spring 80 bearing against a Washer 82 attached tothe neck structure 44 as shown. The sleeve 56 is also provided with twoholes 84 and 86 as shown particularly in FIG. 12, each hole beingadapted to slidably receive respective ball bearings 88 and 90.

In this construction, the ball bearings 88 and 90 cooperate with theneck structure 44 and with the manual actuating means 52 to form amechanical latch for releasably securing the manual actuating means inselective position within the neck structure in a manner which will behereinafter described. As shown, this mechanical latch is substantiallycompletely enclosed within the neck structure 44 utilizing otherwiseunused space within the neck portion normally -used for mounting thecircuit breaker 10 on a control panel or the like, thereby contributingto the miniaturization of the circuit breaker o this invention.

Referring now in greater detail to the terminals 32 and 34, it can beseen by reference FIGS. 1 and 4 that a terminal 32 and a terminal 34 aremounted in each of the circuit breaker compartments 26, 28 and 30 andare associated with fixed electrical contacts 92 and 94 respectivelywithin each of the circuit breaker compartments. That is, as shown inFIGS. 17 and 18, an electrical clontact 92 is attached by welding or thelike to an extension of each terminal 32 so that, when the terminals areheld within matching slots in pairs of clam-shell units forming part ofthe circuit breaker housing, an electrical contact 92 is located infixed position within each of the circuit breaker compartments.

Similarly, as shown in FIGS. 22-24, an electrical contact 94 isassociated with each terminal 34 so that when these terminals are heldwithin matching slots between pairs of clam-shell units in the circuitbreaker housing, a contact 94 is located in xed position within each ofthe circuit breaker compartments. That is, as shown in FIGS. l9-21 achannel member 96 is provided for at* tachment to the terminal 34. Oneange '98 of the channel member is provided with a threaded bore 100 andan adjusting screw 102 is threaded into the bore to engage the oppositeflange 104 of the channel member. The web of the channel member isapertured at 106, is provided with a weld projection 108, and is slottedat 110, the end portions of the channel member web preferably being bentto lie in a plane above the plane of the central portion of the channelmember web as shown particularly in FIG. 20. The channel member, whichis preferably formed of metal of high electrical conductivity, then hasits central web portion welded or otherwise securely attached inelectrically conductive relation to the terminal 34. A thermostaticbimetallic actuator 112, substantialy U-shaped in form, is electricallyconnected at one end to the channel member 96 and at its opposite end tothe electrical contact 94. That is, as shown in FIG. 22, one end of thebimetallic actuator 112 is welded or otherwise secured in electricallyconductive relation to the channel member 96 at the location of the weldprojection 108. As shown particularly in FIG. 24, a rivet 116 passingthrough an insulating bushing 118 in the channel member aperture 106securely attaches the bimetallic actuator 112 to an electricallyconductive strap 120 while supporting the strap and the associated endof the bimetallic actuator in electrically insulated relation to thechannel member 96. The inner surface of the bimetallic actuator isprovided with partial coatings 122 and 123 of plastic material or thelike for assuring the desired electrical insulation between channelmember 96 and the actuator 112 other than at the location of the weldprojection 108. As illustrated in FIGS. 22-24 the connecting strip 120is welded or -otherwise electrically connected to a rigid electricallyconductive support 124 which, in turn, is welded or otherwiseelectrically connected to the contact 94. In this arrangement, each pairof contacts 92 and 94 is adapted to be bridged by a movable contactmeans to close an electrical circuit between respective pairs ofterminals 32 and 34.

In accordance with this invention, each of the cornpartments 26, 28 and30 of the circuit breaker 10 also encloses a catch mechanism 126 whichis illustrated in detail in FIGS. 14 and l5. As shown, the catchmechanism 126 incorporates a generally U-shaped bimetallic supportmember 128 and a T-shaped rigid catch blade 130 which is welded orotherwise securely attached to the ends of the support member to disposean elongated leg 132 of the T-shaped member between the legs of thesupport member. Flexing of the bimetallic member 128 in response to achange in ambient temperature moves the end 134 of the bimetallic member(to the left as shown in FIG. 15) without corresponding movement of thedistal end of the leg 132 of the T-shaped member. A spring member 136 iswelded or otherwise attached to one side of the leg 132 as shown inFIGS. 14 and 15, and a bifurcated cam follower plate 138 is welded orotherwise attached to the opposite side of the leg 132. As shownparticularly in FIGS. 1 and 4, a catch mechanism is pivotally mounted atone end in each of the circuit breaker compartments 26, 28 and 30 bytting the ends 140 of the T-shaped member 130 in slots 142 molded in theclam-shell units forming the circuit breaker housing. In thisarrangement, the spring 136 incorporated in each of the catch mechanisms126 bears against the wall of the circuit breaker housing as indicatedparticularly at 144 in FIG. 4 to bias the catch mechanism toward thecenter of its respective circuit breaker compartment.

In accordance with this invention, the connecting link 72 on the manualactuating means 52 supports a single shaft 146 in the link hole 73, theshaft extending to either side of the link through each of the circuitbreaker compartments 26 and 30 as shown particularly in FIGS. 1 and 3.This shaft 146 is provided with insulating sleeves 148 at either side ofthe connecting link 72. The clam-shell units 12 and 18 are provided withslots 150 and clam-shell units 14 and 16 are provided with slots 152 forpermitting limited vertical movement of the shaft 146 in response tomovement of the manual actuating means S2. As illustrated particularlyin FIG. 8 the casing spacers 20 each have a central aperture 156 whichpermits such vertical movement of the shaft 146 to occur.

The shaft 146 supports three substantially similar bell crank latchmechanisms 158, and 162 within the circuit breaker compartments 26, 28and 30 respectively. Mechanism 160, representative of mechanisms 158 and162, is illustrated in FIG. 27 and is shown to comprise a bell crankhaving a latch part 164 and an extending leg 166, the leg and latch partbeing angularly disposed with respect to each other. The bell crank isadapted to resiliently mount the contact leaf spring assembly 168 (seeFIGS. 25 and 26) and for this purpose the bell crank is recessed at 170to form the shoulders 172, 174, 175 and 176. The contact leaf springassembly 168 preferably includes a leaf spring 78 of beryllium copper orthe like formed with a bight portion therein and includes a contactmember 182 which is secured at one end of the leaf spring. The Contactmember preferably comprises a bilayer material including a layer 184 ofelectrical contact material such as silver and a backing layer 186 ofsteel, nickel or the like 'which is easily welded to the leaf spring178. The leaf spring 178 is provided with an aperture 188 in the bightportion thereof and is provided with an inwardly bent portion 190 bymeans of which the compact leaf spring assembly is resiliently mountedon the bell crank 160. In this arrangement, as illustrated in FIG. 28,the bight portion of the leaf spring 178 is easily compressed and isfitted into the recess 170 in the bell crank 160. The compression of theleaf spring is then released so that the spring expands to engage theshoulders 172, 174, 175 and 176 on the bell crank for securely holdingthe contact leaf spring assembly to the bell crank. As shown in FIG. 25,the leaf spring 178 and the contact member 182 are preferably bifurcatedas indicated at 192. The bell crank member 160 also includes a centralbore 194 adapted to t around the shaft 146 as illustrated in FIGS. 1 and3 to mount the bell crank 160 and its associated contact leaf springassembly 168 for free rotation on the shaft. The bell crank 160 alsoincludes an aperture 196 in the extending leg thereof and, asillustrated in FIG. 4, a helical coil tension spring 198 is connected atone end to the aperture 196 and at its opposite end to a pin 199attached to the wall of the lcircuit breaker housing for biasing thebell crank 160 for rotation (in a counter clockwise direction as viewedin FIG. 4) on the shaft 146.

The latch mechanisms 158 and 162 include comparable bell crank members200 and 202 which have larger central bores than the bell crank 160 formounting the bell cranks 200 and 202 for free rotation on the insulatingsleeves 148 and 150 on the shaft 146 as will be understood. The bellcranks 200 and 202 preferably have bushings 204 and 206 respectivelysecured thereto in coaxial relation to the central bores in the bellcranks to assure that the bell cranks do not cut through the insulatingsleeves 148 and 150 during rotation of the bell cranks. The latchmechanisms 158 and 162 mount respective contact leaf-spring assemblies168, are biased for rotation by springs 198, and are otherwise similarto the latch mechanism 160. As illustrated in FIGS. 1 and 3, the latchmechanisms 158, 160 and 162 are located on the shaft 146 so that thelatch parts of the bell crank thereof are adapted to fit between thebifurcation of the cam followers 138 to engage the extending legs 132 ofcatch blades 130 of the respective catch mechanisms 126 in compartments26, 28 and 30 of the circuit breaker 10 (see FIG. l5).

In accordance with this invention, cam members 208, 210, 212 and 214 arealso mounted for free rotation on the shaft 146 adjacent the latchmechanism 158, 160 and 162. One of these cam members 210, representativeof the other cam members, is illustrated in greater detail in FIG.

7 and is shown to have a central bore 216 appropriately sized formounting the cam for rotation on a shaft 146. The cam is proportioned sothat that when mounted on the shaft 146 closely adjacent to the latchmechanism 160, a cam surface 218 normally bears against the leaf spring178 carried by the latch mechanism 160 and another cam surface 220normally contacts one of the bifurcations of the cam follower 138 on thecatch mechanism 126 located in the circuit breaker compartment 28. SeeFIG. 4. Two connecting rods 222 are welded or otherwise secured to thecam 210 as shown in FIG. 7, these rods eX- tending through slots 224 and226 in the adjacent clamshell unit 16 in the circuit breaker housing asshown in FIGS. 1 and 3. See also FIG. 6. The cam member 208 located inthe circuit breaker compartment 26 is of similar construction to the cammember 210 but has a larger central bore appropriately sized formounting the cam 208 on the insulating sleeve 148 on the shaft 146 aswill be understood. Similar connecting rods 222 are secured to the cam208 to extend through corresponding slots 228 and 229 in the adjacentclam-Shell unit 14 in the circuit breaker housing. In this arrangement,the pairs of connecting rods 222 on the cams 208 and 210 are connectedtogether by means of insulating coupling sleeves 230 pressfitted thereonso that the cams 208 and 210 are locked together for common rotation onthe shaft 146 but are electrically insulated from each other. See FIG.5. An arc shield 232 is preferably mounted on the connecting rodcoupling sleeves 230 within the aperture 156 in the spacer 20 to preventarcing between the circuit breaker compartments 26 and 28 through theslots 224, 226, 228 and 229. As will be understood, the cams 212 and 214are similarly proportioned and coupled together by connection rods 222and sleeves 230 so that cams 212 and 214 are secured together for commonrotation on the shaft 146.

In each of the circuit breaker compartments, a slide or motion-transfermeans 234, comprising a at sheet of insulating fiber-board or the likehaving a central opening 236, is slidably mounted in grooves 238 in theclam-shell units 12, 14, 16 and 18 between the distal or free ends ofthe bimetallic actuators 112 and respective bimetallic members 128 ofthe catch mechanisms 126. The apertures 236 in the motion-transfer meanspermit passage of the Amanual actuator 52 through one of themotion-transfer means while permitting limited horizontal slidingmovement of that motion-transfer means.

If desired, arc shields 240 can be located between the contacts 92 and94 in each circuit breaker compartment as described in the noted earlierfiled application.

The operation of the circuit breaker will now be described.

The position of the circuit breaker parts shown in FIG. 4 is arrived atby pushing the manual actuating means 52 inwardly of the circuit breakerhousing. That is, when the manual actuating means 52 is pressed inwardlyof the housing, the latch plunger 70 and connecting link 72 move themain circuit breaker shaft 146 inwardly of the circuit breaker housingso that the latch parts of the latch mechanisms 158, 160 and 162 becomeengaged with the extending legs 132 of the catch mechanisms 126 locatedin respective circuit breaker compartments 26, 28 and 30. This actionrotates the latch mechanisms 158, 160 and 162 against the bias of thesprings 198 so that the contact members 182 carried by the latchmechanisms are engaged in bridging relation between pairs of contacts 92and 94 in each of the circuit breaker compartments. In this way, acircuit is closed between the terminals 32 and 34 in each of the circuitbreaker compartments. For example, as illustrated in FIG. 4, the circuitclosed in circuit breaker compartment 28 extends from a terminal 32through the contact 92, the contact member 182, the contact 94, support124, connecting strap 120, 'bimetallic actuating member 112, and channelmember 96 to the terminal 34. As the manual actuating means 52 ispressed inwardly of the circuit breaker housing, the latch plunger 70forces the ball bearings 88 and 90 in holes 84 and 86 in the sleeve 56to engage the shoulder 49 in the neck structure 44 for releasablylatching the manual actuating means 52 in the closed-contacts positionillustrated in FIG. 4. While the latch mechanisms 158, and 162 areengaged with a catch mechanism 126, the bias of the springs 198 on thelatch mechanism urges the shaft 146, and therefore the latch plunger 70,upwardly preventing release of the ball bearing engagement with theshoulder 49 in the neck structure 44, thereby maintaining the manualactuating means 52 in closedcontacts position as described in the notedearlier tiled application.

For simultaneous manual opening of the circuits in each of the -circuitbreaker compartments, the manual actuating means 52 is pushed slightlyinwardly of the circuit breaker housing for aligning reduced diameterportions of the latch plunger 70 with the 4ball bearings 88 and 90permitting the ball bearings to move inwardly toward the latch plungeraxis to release their engagement with the shoulder 49 in the neckstructure 44 and for permitting the manual actuating means to move withsnap action to the position shown in FIG. l0 under the bias of thespring 80 and the springs 198. As the manual actu-ating means moves tothe position shown in FIG. l0, the latch mechanisms 158, 160 and 162 aresharply rotated on the shaft 146 for disengaging the contact members 182carried by the latch mechanisms from the xed contacts 92 and 94 in eachof the circuit breaker compartments, thereby opening the circuits ineach of the circuit breaker compartments. It will be noted that thelatch parts of the latch mechanisms 158, 160 and 162 remain inengagement with the catch mechanisms 126 in the respective circuitbreaker compartments during manual opening of the circuit breaker in themanner just described. It will also be noted that the cam members 208,210, 212 and 214 are rotated with the latch mechanisms by reason ofengagement of the cams at 218 with the leaf springs 178 carried 'by thelatch mechanisms. However, as the latch mechanisms 158, 160 and 162 moveupwardly from the center of the circuit breaker housing with the manualactuating means during manual opening of the circuit breaker, the cammembers 210, 212 and 214 rotate with the latch mechanisms without movingthe catch mechanisms 126 in the circuit breaker compartments. That is,although the cam surface 220 of cam members are in contact with the camfollower plates 138 of the catch mechanisms, rotation of the cams duringmanual opening does not exert any camming force on the plates 138.Therefore when the manual actuating means are again pressed inwardly ofthe circuit breaker housing for moving the circuit breaker parts intoclosed-contacts position, the engagement of the latch mechanisms 158,160 'and 162 with the catch mechanisms 126 readily rotates the latchmechanisms for returning the circuit breaker parts to theclosed-contacts position shown in FIG. 4.

When the circuit breaker parts are in the closed contacts position shownin FIG. 4 and the circuit breaker is subjected to a change in ambienttemperature, the bimetallic actuator 112 tends to flex slightly so thatthe upper or free end of the actuator as viewed in FIG. 4 moves slightlyto the left. At the same time the bimetallic member 128 of the catchmechanism 126 also tends to flex in response to the change in ambienttemperature moving the upper or free end of the bimetallic member to theleft as viewed in FIG. 4 Without moving the catch plate 132 incorporatedin the catch mechanism. This simultaneous movement of the bimetallicmembers 128 and 112 causes the motion transfer means 234 also to moveslightly as will be understood. In this way, the circuit breaker 10 isfully compensated for changes in ambient temperature.

However, if the circuit in Iany of the circuit breaker compartments 26,28 or 30 is subjected to an overload current, the passage of thiscurrent through the bimetallic actuator 112 causes heating of theactuator which is independent of any heating of the bimetallic member128 in a catch mechanism 126. Thus the bimetallic actuator will move tothe left as viewed in FIG. 4 moving the motion-transfer means 234 sothat the catch mechanism 126 tends to pivot to the left as viewed inFIG. 4. That is, the motion-transfer means bears against the end 134 ofthe bimetallic member 128 in the catch mech-anism causing the catchmechanism and the catch plate 132 thereof to move to the left. Thus, forexample, when the bimetallic actuator 112 has been suiciently heated inresponse to overload current in the circuit in compartment 28, the catchmechanism 126 in compartment 28 moves suiciently to release itsengagement with the latch mechanism 160 in the compartment forpermitting the latch mechanism to begin to rotate (in a clockwisedirection as viewed in FIG. 4) under bias of the spring 198.

As the latch mechanism 160 is released by the catch mechanism 126 in thecircuit breaker compartment 28, and as the latch mechanism begins torotate in a counterclockwise direction under the bias of a spring 198,the circuit breaker parts are in the position as shown in FIG. ll. Thatis, the contact member 182 has been disengaged from the contacts 92 and94 in the circuit breaker compartment 28. At this point it would appearfrom FIG. 11 that the latch plunger 70 is no longer restrained fromdownward movement by the latch mechanism 160 so that the latch plunger70 could move downwardly permitting the latching ball hearings 88 and 90to disengage from the shoulder 49 in the neck structure 44, therebypermitting the manual actuating means 52 to move outwardly of thecirciut breaker housing to open-contacts position under the bias of thespring 80. However, latch mechanisms 158 and 162 would remain engagedWith catch mechanism 126 in the respective circuit breaker compartments26 and 30 and the engagement of these latch mechanisms with theirrespective catch mechanism would be suicient to prevent the latchplunger 70 from moving downwardly. In accordance with this invention,however, the cam members 210 and 212 located in a circuit breakercompartment 28 closely adjacent the latch mechanism 160 are positionedso that, during the described counter-clockwise rotation of the latchmechanism 160, engagement of the leaf spring 178 carried 4by the latchmechanism with the cam surfaces 218 of the cams 210 and 212 causes thecams 210 and 212 to rotate with the latch mechanism 160. This rotationof these cam members then serves to open the circuits in the adjacentcircuit breaker compartments 26 and 30.

That is, as is illustrated particularly in FIG. 16, cam member 210 islocked together with cam member 208 for common rotation therewith byconnecting rods 222 and couplings 230. Therefore, rotation of the cammember 210 is accompanied by rotation of the cam member 208, the camsurface 220 of the cam 208 then bearing against one of the bifurcationsof the cam follower plate 138 incorporated in the catch mechanism 126located in circuit breaker compartment 26. In this way, the cam 208bears against and pivots the catch mechanism 126 in the circuit breakercompartment 26 until the catch plate 132 thereof releases its latchingengagement with the latch mechanism 158. Simultaneously, rotation of thecam member 212 with the latch mechanism 160 causes rotation of the cammember 214 to release engagement of the catch mechanism 126 in circuitbreaker compartment 30 from the latch mechanism 162. The latchlmechanisms 158 and 162 then rotate in response to the bias of springs198 attached thereto for opening the circuits in circuit breakercompartments 26 and 30. When all lof the catch mechanisms 158, 160 and162 are disengaged from their respective catch mechanisms in thismanner, the latch plunger 70 is free to move downwardly, permitting thelatching balls 88 and 90 to release engagement with the shoulder 49 inthe neck structure 44, and the manual actuating means 52 moves sharplyto open-contacts position under the bias of the spring 80. In this way,the circuit breaker is adapted to open all circuits in a three-phasecircuit upon the occurrence of an overload current in any one of thecircuits and, by moving the manual actuating means to open circuitposition, gives visual indication that the circuit breaker has beentripped. In this regard, it will be noted that opening of any circuit inthe circuit breaker requires rotation of one of the latch mechanisms158, and 162 and that as these latch mechanisms move at about the sametime with movement of the cam members 208, 210, 212 and 214, theoccurrence of an overload current in any circuit breaker circuit resultsin substantially simultaneous opening of all circuit breaker circuits.

It will be noted that the three-phase or multipole circuit breaker 10`of this invention is adapted for trip-free operation. For example, ifthe bimetallic actuator 112 has moved in response to an overload currentin the circuit through circuit breaker compartment 28 resulting inopening of all of the circuit breaker circuits in the manner justdescribed, and if an attempt is made to close the circuit breakercircuits by manually depressing the manual actuating means 52 while thebimetallic actuator 112 in circuit breaker compartment 28 remainsconditioned by said overload current, the latch mechanism 160 cannotengage a catch mechanism 126 in compartment 28 so that the latchmechanism 160 cannot be rotated to reclose the circuit in compartment28. In addition, as the manual actuating means 52 are moved inwardly ofthe circuit breaker, engagement of the cam surfaces 220 on the cams 208and 214 with the catch mechanisms 126 in circuit breaker compartments 26and 30 prevent engagement of the latches 158 and 162 with the catchmechanisms in compartments 26 and 30, thereby preventing closing ofcircuits through those compartments.

It will also be understood that, if it is desired to change thecalibration of the circuit breaker 10 to provide for automatic operationof the circuit breaker in response to different overload currents in thebreaker circuits, the adjusting screws 102 can be located for adjustingthe response of the bimetallic actuators 112 in each of the circuitbreaker compartments. As such calibration is adequately described in thenoted earlier tiled, copending application, such calibration is notfurther described herein and it be understood that calibration isperformed in the manner described in said copending application.

It can be seen that, in the multiple circuit breaker of this invention,each of the breaker circuits is adapted to automatically open inresponse to overload current in the circuit. The response of the circuitbreaker to current conditions in said circuit is independent of thecurrentconditions in any of the other breaker circuits. Yet when one ofthe breaker circuits opens in response to an overload current therein,the other breaker circuits are also opened automatically'andsubstantially simultaneously. The circuit breaker is also manuallyoperable for opening and closing breaker circuits without subjecting thecurrent-responsive breaker means to such use as would upset thecalibration thereof. The multiple circuit breaker is easily calibrated,is ambient-compensated and is fully trip-free, Further, the circuitbreaker is exceedingly compact and rugged even though it has the widecapabilities noted above.

It should be understood although particular embodiments of the circuitbreaker of this invention have been described by way of illustration,this invention includes all modications and equivalents thereof fallingwithin the scope of the appended claims.

I claim:

1. A multiple circuit breaker comprising a housing, a plurality of xedcontact means on said housing, manual actuating means mounted on saidhousing for movement between first and second switch positions, a shaftcarried by said actuating means for movement therewith between saidswitch positions, a plurality of latch means .mounted for individualrotation on said shaft, a plurality of movable contacts mounted onrespective latch means for engaging and disengaging respective fixedcontact means for .making and breaking respective circuits through saidcontact means, means biasing said latch means for rotation to opencircuit position, a plurality of catch means engaging respective latchmeans for normally 'holding said latch means in closed circuit positionagainst said bias, current responsive means in respective circuits eachadapted to release its respective catch means from its respective latch.means in response to a Selected current in its respective circuit, anda plurality of cam means rotatable on said shaft for releasingrespective catch means from said latch means, at least one of said cammeans being engageable by each latch means during rotation of said latchmeans in response to said bias, each of said cam means beinginterconnected with at least another of said cam means for commonrotation therewith to release at least a pair of said catch .means inresponse to occurrence of said selected current in any one of saidcircuits.

2. A multipole switching device comprising a housing, a plurality offixed contact means on said housing, manual actuating means mounted onsaid housing for movement between iirst and second switch positions, ashaft carried by said actuating means for movement therewith betweensaid switch positions, a plurality of first latch means rotatablymounted on said shaft, movable contact means mounted on respective latchmeans, a plurality of catch means engageable with respective latch meansduring movement of said actuating means to said second switch positionfor rotating said latch means to engage said movable contact means withrespective iixed contact means to close respective circuitstherethrough, means biasing respective latch means for rotation todisengage said movable and fixed contacts, a plurality ofcurrent-responsive means interposed in respective circuits to move inresponse to overload current in said circuits for disengaging respectivecatch means from said latch means to permit rotation of said latch meansin response to said bias to open respective circuits, a plurality of cammeans rotatable on said shaft, at least one of said cam means beingengageable and rotatable by each of said latch means during rotation ofsaid latch means in response to said overload current, pairs of said cammeans being connected for common rotation to disengage all of said catchmeans from said latch means when one of said latch means rotates inresponse to said overload current, means biasing said manual actuatingmeans to said first switch position, and second latch means normallyholding said manual actuating means in said second switch position Whilesaid latch means and catch means are engaged, said second latch meansbeing releasable upon manual movement of said manual actuating means forpermitting said actuating means to move to said first switch position toopen said circuits.

3. A trip-free, ambient-compensated, multipole switching devicecomprising a housing, a plurality of fixed contact means on saidhousing, manual actuating means mounted on said housing for movementbetween first and second switch positions, a shaft carried by saidactuating means for movement therewith between said switch positions, aplurality of iirst latch -means rotatably mounted on said shaft, movablecontact means mounted on respective latch means, catch means normallyadapted to engage respective latch means during movement of saidactuating means to said second switch position for rotating said latchmeans to engage said movable contact means with respective fixed contactmeans to close respective circuits therethrough, means biasing saidlatch means for rotation to disengage said movable and dixed contacts, aplurality of first thermally responsive bimetallic means mountingrespective catch means and adapted to move independently of said catchmeans in response to changes in ambient temperature, a plurality ofsecond thermally responsive means adapted to move in response to changesin ambient temperature, said second thermally responsive means beinginterposed in respective circuits and being adapted to move in responseto overload current in said circuits, a plurality of motion transfermeans between respective first and second thermally responsive meansadapted to move said respective :lirst thermally responsive meanstogether with said catch means to disengage said catch means from saidlatch means in response to movement of said respective second thermallyresponsive means when conditioned by overload current therethrough forpermitting said latch means to rotate in response to said bias to openrespective circuits, a plurality of cam means rotatable on said shaft,at least one of said cam means being adapted to be engaged and rotatedby each of said latch means during rotation of said latch means inresponse to said overload current, pairs of said cam means beingconnected for common rotation to disengage all of said catch means fromsaid latch means when any one of said latch means rotates in response tosaid overload current, means biasing said manual actuating means to saidiirst switch position, and second latch means normally holding saidmanual actuating means in said second switch position while said latchmeans and catch means are engaged, said second latch means beingreleasable upon manual movement of said manual actuating means forpermitting said actuating means to move to said first switch position toopen said circuits.

4. A trip-free, ambient-compensated, multipole switching devicecomprising a housing, lixed contact means on said housing, manualactuating means mounted on said housing for movement between rst andsecond switch positions, a shaft carried by said actuating means formovement therewith between said switch positions, a plurality of firstlatch means rotatably mounted on said shaft, movable contact meansmounted on respective latch means, a plurality of thermally responsiveblade members each pivotally mounted at one end on said housing andhaving its opposite Iend free for movement in response to changes inambient temperature, a plurality of catch blades attached at one end tosaid pivotally mounted ends of respective thermally responsive blades,said catch blades having their opposite ends disposed to normally engagerespective latch means during movement of said actuating means to saidsecond switch position for rotating said latch means to engage saidmovable contact means with respective fixed contact means to closerespective circuits therethrough, means biasing said latch means forrotation to disengage said movable and fixed contacts, a plurality ofsecond thermally responsive members each having an end adapted to movein response to changes in ambient temperature, said second thermallyresponsive means being interposed in respective circuits and beingadapted to move at said ends in response to overload current in saidcircuits, motion-transfer means between said movable ends of respectivelirst and second thermally responsive means adapted to move said iirstthermally responsive means together with said catch blades to disengagesaid catch blades from said latch means in response to movement of saidrespective second thermally responsive means when conditioned byoverload current therethrough for permitting said latch means to rotatein response to said bias to open respective circuits, a plurality of camfollower plates attached to respective catch blades, a plurality of cammeans rotatable on said shaft to engage respective cam follower plates,at least one of said cam means being adapted to be engaged and rotatedby each of said latch means during rotation of said latch means torespond to said overload current. Pairs of said cam means beingconnected for common rotation to disengage all of said catch blades fromsaid latch means when any one of said latch means rotates in response tosaid overload current, means biasing said manual actuating means to saidtirst switch position, and second latch means 2,813,168 11/ 1957Mascioli et al 337-46 X normally holding said manual actuating means insecond 3,171,922 3/ 1965 Stokes 337-74 switch position While said latchmeans and catch means 3,211,862 10/1965 Ellenberger 337-46 are engaged,said second latch means being releasable 3,263,047 7/ 1966 Jencks 337-45upon manual movement of said manual actuating means 5 3,361,882 1/ 1968Clarke 337-74 for permitting said actuating means to move to said rstswitch position to open Said circuits, BERNARD A. GILHEANY, PrlmaryEXammer References Cited H. B. GILSON, Asslstant Exammer UNITED STATESPATENTS 10 U.S. Cl. X.R.

2,367,382 1/ 1945 Taylor .337-46 337-46

